Under the operational and environmental conditions of such industrial sectors as manufacturing, power transmission and utilities (gas, electricity and water), etc, network interconnections are always challenged. In the early stages, wired connections were often adopted, but under the inclement working conditions of factories, this was inconvenient, and it easily caused failures, resulting in network interruptions. So wireless connections became the preferred choice. The present document will introduce the development trends of the Industrial Internet of Things (IIoT) and relevant solutions.
Wireless Networks Providing Higher Mobility and Flexibility
In an industrial environment where wired infrastructures are insufficient or difficult to realize, wireless networks provide more strengths, and increases many new possibilities, such as higher mobility and flexibility, simpler network management, and lower construction cost. With changing demands, the use of other wireless protocols is also increasing. IIoT may be realized through a wireless network, and there are several options for selection, but it is challenging to select the right solutions.
Power consumption is an important consideration in a wireless IIoT network. For wired networks, the power required for driven connection is factually provided by the connection itself. However, for a wireless network, the power must be additionally provided or the device collects the power. This means that the power consumption is the key consideration of a wireless IIoT network. Therefore, wireless IIoT device must be leveraged in respect of output power, duty ratio and throughput, etc.
The coverage is closely related to the operating frequency of the wireless network. Those components working in the Sub-GHz scope generally have a larger coverage than those working within 2.4GHz (for the given power). However, a wireless mesh network may help extend the coverage of 2.4GHz. Currently, there are many prevailing mesh technologies, like Zigbee, Thread, Bluetooth Mesh, etc. Since many standards and the 2.4GHz frequency bands are adopted, these protocols are essential to the future development of the IIoT. Therefore, it is estimated that the IIoT will adopt the protocols running between the 2.4GHz and Sub-GHz band.
Multi-protocol Radios Have More Strengths and Benefits
The lower power wide area network (LPWAN) (like LoRa and Sigfox) and the cellular variants like NB-IoT and LTE-M will work within the Sub-GHz band and maintain relatively lower data bandwidth (each message of 10 bits). LPWAN is able to realize coverage up to tens of kilometers. These technologies are very suitable for those emerging infrastructures like smart cities and remote monitoring, etc. The distance between nodes is very large, but the data to be exchanged is relatively fewer. However, they are not suitable for smart factories. This is because, for smart factories, the bandwidth and delay performance are more important than the coverage.
Since Sub-GHz technology has strengths and advantages surpassing those of the 2.4GHz frequency spectrum, the IIoT adopts Sub-GHz technology more often. Proprietary protocols are still popular in the Sub-GHz band. This is partly attributable to the popularity of legacy technologies.
Multiprotocol Technology simplifies Bluetooth control of devices such as smart meters on sub-GHz networks.
Just like the combination of wired and wireless technologies, it was ideal to realize the best connection. However, now the solution may not be one single wireless technology, but combining the strengths and benefits of both. The protocols working in the Sub-GHz band provide many benefits, but it only provides limited bandwidths, and provides simple interfaces for those standard devices like PCs, laptops, tablets, smart phones, etc. The multi-protocol solution supporting Bluetooth and Sub-GHz connections not only provides the standard 2.4GHz based connection, but also may be used for man-to-machine interaction for the network of M2M adopting Sub-GHz technology.
Wireless Gecko Proprietary Protocol Ideal for IIoT
To speed up the development of wireless IIoT application products, Silicon Labs has launched the wireless Gecko proprietary protocol system-on-a-chip (SoC) solution. The EFR32FG22 wireless Gecko proprietary protocol – SoC series - is part of the wireless Gecko series. The EFR32FG22 wireless Gecko SoC is ideal for energy-friendly proprietary protocol connections for IIoT devices. The wireless Gecko applications cover electronic shelf labels, home and building automation and security, industrial automation, and commercial and retailing lighting and sensing.
This SoC solution combines a 38.4 MHz Cortex-M33 and a high-performance 2.4 GHz radio, in order to provide industrial-leading energy saving wireless SoC for IIoT connection applications. The EFR32FG22 integrates a 32-bit ARM® Cortex®-M33 core, with a maximum working frequency of 38.4 MHz, and also configured with DSP instructions and floating-point units, thus realizing highly efficient signal processing. It is configured with flash memory up to 512kB and RAM of 32kB, and has an energy saving RF core with a lower active current and sleep current, as well as integrating PA, with TX power up to 6 dBm(2.4 GHz). The radio receiving current is 2.5 mA. Safe starting can be triggered by the root of trust and safe loading program (RTSL), while having the optional RFSENSE with selective OOK mode.
Multiple Protocols and Peripherals Supported
Under the condition of 250 kbps O-QPSK DSSS, the sensitivity of the EFR32FG22 RF performance is -102.3 dBm, -98.9 dBm under the condition of 1 Mbit/s GFSK, and -96.2 dBm under the condition of 2 Mbit/s GFSK. The supported modulation formats include 2 (G)FSK, which can configurable shaping, and support OQPSK DSSS, (G)MSK, and proprietary protocols.
EFR32FG22
The EFR32FG22 is built in with a wide range of MCU peripherals for selection, including the Analog to Digital Converter (ADC), and up to 26 general I/O pins with output status maintenance and asynchronous interrupt functions, 8-signal-channel DMA controllers, and a 12-signal-channel peripheral reflex system (PRS).
The EFR32FG22 has a wider working scope, and supports a single power line of 1.71V – 3.8V, with a working temperature between -40℃ and 85℃, as well as supporting AES128/256, SHA-1, SHA-2 (up to 256 bit), ECC (up to 256 bit), ECDSA, and ECDH hardware encryption speeds. The EFR32FG22 adopts two kinds of package formats, including QFN40 (5 mm x 5 mm x 0.85 mm) and QFN32 (4 mm x 4 mm x 0.85 mm).
Conclusion
Currently, the companies and governments of the world are recognizing the benefits to the industrial environment from wireless connections, like: improving procedures and enhancing productivity, the demand for more smart operations in factories, cities, offices and homes, etc. In addition to the sensors and drivers, the IIoT is also required to realize cloud connections and big data for global interconnection, resulting in revolutionary changes for industrial applications. Silicon Labs’ wireless Gecko proprietary protocol SoC solution will satisfy various demands of the IIoT, which is ideal to enter the relevant application markets.
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